Effects of Vessel Wall Elasticity on Blood Flow

血管壁弹性对血流的影响

基本信息

批准号：
04670845
负责人：
SEKI Junji
金额：
$ 1.34万
依托单位：
National Cardiovascular Center Research Institute
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

In vitro and in vivo experiments were conducted to study the effects of the vessel wall elasticity on the blood flow characteristics focusing on thegeneration and development of blood flow turbulence and on the propagation of flow pulse in microvessels, respectively.In in vitro experiments, a fully developed pulsatile flow (sinusoidal flow in addition to mean flow) was measured by a laser-Doppler anemometer. The velocity waveforms and the velocity profiles in the tube cross-section were obtained under various conditions of pulsatile flow. When the flow was not turbulent, the velodcity waveforms and the velocity proviles agreed well with the theoretical predictions. Regarding the turbulence transition, the centerline velocity was recorded as the mean Reynolds number was increased with a fixed frequency and amplitude of pulsation. The flow became turbulent in the deceleration phase when the mean Reynolds number was larger than a critical value, the transition Reynolds number. The transis … More ion Reynolds number was 2400 at the modulation Reynolds number of 880 and the freqyency parameter of 5.9. Considering the transision Reynolds number of steady flow was 2000, it means that the flow is stabilized under the pulsatile condition.In in vivo experiments, propagation of flow pulse was studied in microvascular networks of rat mesentery by a fiber-optic laser-Doppler anemometer microscope (FLDAM). The mean flow rate, amplitude of the flow pulsation, phase lag of the microvascular flow relative to the carotid arterial pressure were determined in arterioles, capillaries and venules. The arterio-venous distributions of the mean flow, flow amplitude and phase lag were analyzed based on an idealized model of the microvasculature. The difference observed in the distributions between spontaneously hypertensive rats (SHR) and normotensive control rats (WKY) were explained from the theoretical model by the rarefaction of small arterioles in SHR.Thepropagation velocity of flow pulse was also measured in arterioles. The elastic modulus of the vessel wall estimated from the propagation velocitywas in the range from 2x10^6 to 2x10^7 dyn/cm^2, which was in the same order of the elastic modulus for large arteries. Less

通过体外和体内实验，研究血管壁弹性对血流特性的影响，分别关注血流湍流的产生和发展以及微血管内血流脉冲的传播。通过激光多普勒风速计测量了脉动流（除了平均流之外的正弦流），获得了不同脉动条件下的速度波形和管横截面的速度分布。当流动不是湍流时，速度波形和速度轮廓与湍流转变的理论预测非常吻合，中心线速度被记录为平均雷诺数随着脉动流动的固定频率和幅度而增加。当平均雷诺数大于临界值时，在减速阶段变得湍流，过渡雷诺数在调制雷诺数处为 2400。考虑到稳定流的转变雷诺数为880，频率参数为2000，这意味着在脉动条件下血流是稳定的。在体内实验中，通过以下方法研究了血流脉冲在大鼠肠系膜微血管网络中的传播。光纤激光多普勒风速计显微镜 (FLDAM) 测量微血管血流的平均流速、血流脉动幅度、相位滞后。相对于颈动脉压力，在小动脉、毛细血管和小静脉中确定了平均流量、流量振幅和相位滞后的动静脉分布，并基于微脉管系统的理想化模型来分析观察到的自发性高血压之间的分布差异。大鼠（SHR）和正常血压对照大鼠（WKY）从理论模型上解释为SHR中小动脉的稀疏。还测量了小动脉中的血流脉冲，根据传播速度估计的血管壁弹性模量在 2x10^6 至 2x10^7 dyn/cm^2 范围内，与大动脉的弹性模量处于同一数量级。。较少的